Auxiliary battery



FIG. 1 is a perspective view of an auxiliary battery showing our new design;

FIG. 2 is a front view thereof;

FIG. 3 is a rear view thereof;

FIG. 4 is a top view thereof;

FIG. 5 is a bottom view thereof;

FIG. 6 is a left side view thereof; and,

FIG. 7 is a right side view thereof.

The broken lines shown in the drawings are included for purposes of illustrating portions of the auxiliary battery and form no part of the claimed design. 

CLAIM The ornamental design for an auxiliary battery, as shown and described. 